Rotating speed adjusting device



Allg- 14, 1962 KATASHI INOUE ROTATING SPEED ADJUSTNG DEVICE 2 Sheets-Sheet 1 Filed NOV. 27. 1959 INVENTOR. KRT/[SHI /NUE' Aug. 14, 1962 KATASHI lNoUE ROTATING SPEED ADJUSTING DEVICE 2 Sheets-Sheet 2 Filed Nov. 27, 1959 r rinvii/ Inventar afforneys 3,049,098 Patented Aug'. 14, 1962 3,049,098 ROTATING SPEED ADJUSTING DEVICE Kataslai Inoue, 738 Moto-Machi-ll-Chome, Naniwadru, Osaka City, Japan Filed Nov. 27, 1959, Ser. No. 855,573 Claims priority, application Japan Dec. 16, 1958 3 Claims. (Cl. 121-423) The present invention relates to a device for adjusting a rotational tool or the like which is mounted on a shaft and driven by an air driving means.

It is yan object of the present invention to provide such an .adjusting device which is highly eflicient, which is easily operated despite its simple structure, and which reacts `to change the speed of the tool depending on the load on the tool.

The device according to the invention comprises a spur gear which is driven by the `air driving means for the tool, and a coupling is provided around the spur gear which has Ian internal gear meshing with the spur gear. 'Y

A helical gear is provided on the outside of the coupling, and the shaft for the tool has la hollow shaft end around the coupling with an internal helical gear meshing with the helical gear on the coupling. Spring means are provided in engagement with the coupling urging it iaway from the shaft. A cylindrical exhaust valve member is mounted on said coupling, which member has at least one air exhaust conduit along a portion of the outer surface thereof. A housing is positioned around the exhaust valve member which has a cylindrical inner wall within which the exhaust valve member slides. The housing has an inlet chamber into which air from the air driving means is vented, :and it also has an outlet chamber vented to the atmosphere. The cylindrical wall around the vialve member has apertures therein lopening out of the inlet chamber and with which the exhaust conduit along the exhaust valve is aligned, and the said wall has ya further rst aperture yand ia second aperture opening into the exhaust chamber, both further apertures being aligned with the exhaust conduit and being spaced such that when a load on the tool causes the coupling to move along the spur gear, the valve member is also moved to cover or uncover the second aperture and thereby increase `or decrease the flow of air through the lair driving means.

A preferred embodiment of the invent-ion will now be described more particularly, reference being made to the accompanying drawings, in which:

FIG. l is a sectional view of an air driven grinding tool having the adjusting device according to the present invention incorporated therein;

FIG. 2 is a sectional View taken along line 2-2 of FIG. l;

FIG. 3 is la sectional view taken along line 3-3 of FIG. l;

FIG. 4 is a sectional view taken along line 4-4 of FIG. l; and

FIG. 5 is a vertical cutaway view of the portion of the tool of FIG. l having the 'adjusting device therein.

As seen in the figures, the tool has a rotatable shaft 5 mounted in bearing 2 and 3 in ya cylinder 4 within a handle 1. A spur gear 7 is mounted on the end 6 of the shaft 5, yand meshes with an internal spur gear 10 on a coupling 9 `around the spur gear 7. A helical gear 11 is formed on the outside of the coupling `9, :and it meshes with an internal helical gear 12 on the inside of `a hollow shaft end 13 on one end of the tool shaft 12. As an example of a tool, there is shown a grinding wheel 24 on the end of the shaft 12.

A spring 15 is positioned within the hollow end 13, and bears on shoulder 14 on the coupling 9, urging coupling 9 away from the shaft 12.

An exhaust valve member 8 is slidably positioned within housing 16, yand the valve member is connected to the coupling 9 by a bearing 8a which causes the valve member to slide when the coupling 9 moves but not to partake of the rotational movement of the coupling.

An inlet chamber 17 is provided between housing 16 and handle 1 which receives air from the air driving .means through passages 28. The housing 16 has apertures 20 therein which open into air exhaust conduit 19 which extends ialong the surface of the valve member 8. An exhaust chamber 18 is also provided between the housing 16 and the handle 1 which is vented to the atmosphere through apertures '23. Between the exhaust chamber 18 and the exhaust conduit 19 in the valve member `are a series of first apertures 21 extending through the housing 16, and these apertures 21 are positioned so that they are always open to the exhaust conduit 19. Spaced -along the cylindrical housing 16 from the first apertures 21 are a series of second apertures 22 which open into the exhaust chamber 18 and which are uncovered so as to open into the exhaust conduit 19 along the valve member 8 when the valve member is moved in response toa `change in the load on the tool on the end of shaft 12.

To drive the tool, air is fed through a valve member 29 in the end of the handle 1 and through air conduits 25 in the handle 1. It impinges .against v'anes 27 mounted in the hub 26 of shaft 5 in such :a manner that they can yield freely to the air pressure and return to their normal position. From the Varies the air is led to the inlet charnber 17 through 4apertures 28.

`In operation, as the air is fed to the vanes, the vanes will act on the shaft 5 to rotate it, `and the tool 24 is vdriven through the spur gears 7 and 10, the coupling 9, the helical gears 11 and 12' and the hollow shaft end 13 and shaft 12. The 'air leaving the vanes passes into the inlet chamber 17 through apertures 28, `and then through the apertures 28 and along the exhaust conduit 19 in the valve member 8. In the normal operation of the tool, the valve member 8 will lbe positioned so that the exhaust conduit 19 uncovers yonly one set of rapertures 21 opening into the exhaust chamber 18. The lair thus passes through these apertures 21 from the exhaust conduit, passes 4through the exhaust chamber 18 and is vented to the atmosphere through apertures 23.

However, when a load is imposed on the tool 24 which causes it to slow down, the shaft 5 will then tend to rotate faster than the shaft 12. The result of this is that the helical gears 11 `and 12 will cause the coupling 9 to move .along the shaft 5 against the action of spring 15, and in the case where `the tool slows down, the gears are `arranged so that the movement of the coupling is toward the shaft 12. The valve member 8 is thus moved along the inside of the housing 16, and the exhaust conduit 19 uncovers the second set of apertures 22;. This permits more air to pass through the exhaust conduit, and therefore permits more air to pass through the vanes 27, aperture 28 'and inlet chamber 17. The shaft 5 then supplies more power to the shaft 12 through the gearing and coupling for as long as the load tends to retard the speed of the tool. When the load falls off, the spring 15 moves the coupling away from shaft 12, and the reverse of the `above described action takes place, causing the parts to resume the positions for normal openation.

It is thought that the invention `and its advantages will be understood from the foregoing `description and it is apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described `and illustrated in the `drawings being merely a preferred embodiment thereof.

I lclaim as my invention:

l. A device for adjusting the rotational speed of a rotating tool or the like mounted on a shaft and driven by an air driving means, said device comprising a spur gear driven by said air driving means, a coupling around said gear and having an internal gear meshing with said spur gear and :a helical `gear on the outside thereof, a hollow shaft end around said coupling and connected to the shaft on which the tool is mounted and having an internal `helical gear meshing with the helical gear :on said coupling, spring means engaged with said coupling urging it -away from the shaft on which said tool is mounted, a cylindrical exhaust valve member 0n said coupling, said exhaust valve member having at least one `air exhaust conduit along a portion of the length of the outer surface thereof, a housing yaround said exhaust valve member and having la cylindrical inner wall within which said exhaust valve member slides, said housing having an inlet chamber therein into which air from the air driving means is vented and having :an outlet chamber vented -to the atmosphere, said cylindrical wall having apertures therein opening out of said inlet chamber and with which said exhaust conduit along said exhaust valve member is aligned, and said cylindrical wall having at least a iirst further aperture :and at least one second further aperture therein opening into said exhaust chamber and with which said exhaust conduit is aligned, said second further aperture being spaced from said first further aperture and normally being out of communication with said exhaust conduit, whereby when a load is applied to the tool and the rotational speed thereof decreases, said coupling is moved toward said hollow shaft and said exhaust valve member moves to `bring said exhaust conduit and said second further aperature into register to permit more air -to pass through said air `driving means.

2. A device for adjusting the rotational speed of a rotating tool or the like mounted on la shaft and driven by an lair driving means, said device comprising a gear member, a coupling meshed with said gear member, and a hollow shaft end member meshed with said coupling, one of said members being driven by said air `driving means and the other being connected to the shaft with the tool thereon, and one of said meshing connections having helical teeth, spring means engaged with said coupling urging it away from the shaft on which said tool is mounted, la helical exhaust valve member on said coupling, said exhaust valve member having at least one air exhaust conduit along a portion of the length of the outer surface thereof, a housing `around said exhaust valve member and having a cylindrical inner wall within whic said exhaust valve member sli-des, said housing having an inlet `chamber therein into which air from the :air driving means is vented and having an outlet chamber vented to the atmosphere, said cylindrical wall having apertures therein :opening out of said inlet chamber and with which said exhaust conduit lalong said exhaust valve member is aligned, and said cylindrical wall having at least a iirst further aperture and at least one second further aperture therein opening into said exhaust :chamber and with which said exhaust conduit is aligned, said second further aperture being spaced from said first further aperture #and normally being out of communication with said exhaust conduit, whereby when a load is applied to the tool and the rotational speed thereof decreases, said coupling is moved toward said hollow shaft and said exhaust valve member moves to bring said exhaust conduit and said second further aperture into register to permit more air to pass through said air driving means.

3. A device for adjusting the rotational speed of a rotating tool or the like mounted on a shaft `and driven by an air driving means, said device comprising a gear member, a coupling meshed with said gear member, and a hollow shaft and member meshed with said coupling, one of said members being driven by said air driving means and the other being connected to the shaft with the tool thereon, `and one of said meshing connections having helical teeth, spring means engaged with said coupling urging it away from the shaft on which the tool is mounted, sliding exhaust valve means on said coupling, and a housing in which said members and coupling and exhaust valve means are housed, said housing having air apertures therein between the air driving means and the outside atmosphere, at least a portion of said air apertures being uncovered and covered by movement of said sliding exhaust valve means.

References Cited in the iile of this patent UNITED STATES PATENTS 2,080,973 Speth May 18, 1937 2,464,997 ShafI" Mar. 22, 1949 2,545,453 Forss Mar. 20, ,1951 2,570,009 Schmid Oct. 2, 1951 2,812,922 Blount et al Nov. 12, 1957 2,905,149 Swanson Sept. 22, 1959 

